Applications of steel-plate composite structures for nuclear modular construction

Abstract: Despite being the world’s second most important low-carbon source of electricity, the development of nuclear capacities is limited and does not comply with the International Energy Agency’s Sustainable Development Scenario. One of the main reasons for this lack of development is high and increasing costs of new nuclear capacities. In fact, capital costs can account for more than 80% of the Levelized Cost of Energy of a new nuclear power plant. Design accounts for about 10% and construction accounts for about 20% of the total capital cost.The importance of design and construction in nuclear power plants’ costs is partly due to limitations of traditional construction methods regarding both technical possibilities and realization schedules. Modular construction methods are proposed to reduce new nuclear power plants’ construction costs, and in particular steel-plate composite structures modular construction. Steel-plate composite structures consist of a structural interaction between thin steel plates and precast concrete. The aim of this thesis was to evaluate the capacity of modular construction, using steel-plate composite panels, to fulfil nuclear safety and functional requirements; as well as to identify potential related gains and opportunities. Advantages and constraints of steel-plate composite modules were identified in scientific literature and intergovernmental opportunity studies, and were related to the specificities of nuclear structures’ design and construction.Steel-plate composite structures modular construction is based on the manufacturing of steel concrete composite modules outside of the civil works site. The higher productivity of workshops and the possible task parallelization may lead to significant construction schedules shortening and capital costs reduction. In addition, steel-plate composite modules offer new technical possibilities which may help solving some constructability issues. However, steel-plate composite structures modular construction requires a reconsideration of the traditional design and construction methods, as they imply new challenges and constraints. In particular, the modularization issue should be addressed as soon as possible in the design, and the module manufacturing capacities should be quickly identified or created in order to deliver properly manufactured modules on-time.Considering the advantages and constraints of steel-plate composite structures modular construction, it appears that steel-plate composite modules may fit advantageously most of the nuclear design requirements. However, due to the lack of feedback, it is proposed that the usage of steel-plate composite modules be limited to critical concrete structures of the containment building. In particular, it appears that the containment dome and the reactor pit construction may benefit from steel-plate composite structures construction methods.